---
title: Record Token Usage after Streaming User Interfaces
description: Learn how to record token usage after streaming user interfaces using the AI SDK and React Server Components
tags: ['rsc', 'usage']
---

# Record Token Usage after Streaming User Interfaces

When you're streaming structured data with [`streamUI`](/docs/reference/ai-sdk-rsc/stream-ui),
you may want to record the token usage for billing purposes.

## `onFinish` Callback

You can use the `onFinish` callback to record token usage.
It is called when the stream is finished.

```tsx filename='app/page.tsx'
'use client';

import { useState } from 'react';
import { ClientMessage } from './actions';
import { useActions, useUIState } from '@ai-sdk/rsc';
import { generateId } from 'ai';

// Allow streaming responses up to 30 seconds
export const maxDuration = 30;

export default function Home() {
  const [input, setInput] = useState<string>('');
  const [conversation, setConversation] = useUIState();
  const { continueConversation } = useActions();

  return (
    <div>
      <div>
        {conversation.map((message: ClientMessage) => (
          <div key={message.id}>
            {message.role}: {message.display}
          </div>
        ))}
      </div>

      <div>
        <input
          type="text"
          value={input}
          onChange={event => {
            setInput(event.target.value);
          }}
        />
        <button
          onClick={async () => {
            setConversation((currentConversation: ClientMessage[]) => [
              ...currentConversation,
              { id: generateId(), role: 'user', display: input },
            ]);

            const message = await continueConversation(input);

            setConversation((currentConversation: ClientMessage[]) => [
              ...currentConversation,
              message,
            ]);
          }}
        >
          Send Message
        </button>
      </div>
    </div>
  );
}
```

## Server

```tsx filename='app/actions.tsx' highlight={"57-63"}
'use server';

import { createAI, getMutableAIState, streamUI } from '@ai-sdk/rsc';
import { openai } from '@ai-sdk/openai';
import { ReactNode } from 'react';
import { z } from 'zod';
import { generateId } from 'ai';

export interface ServerMessage {
  role: 'user' | 'assistant';
  content: string;
}

export interface ClientMessage {
  id: string;
  role: 'user' | 'assistant';
  display: ReactNode;
}

export async function continueConversation(
  input: string,
): Promise<ClientMessage> {
  'use server';

  const history = getMutableAIState();

  const result = await streamUI({
    model: openai('gpt-3.5-turbo'),
    messages: [...history.get(), { role: 'user', content: input }],
    text: ({ content, done }) => {
      if (done) {
        history.done((messages: ServerMessage[]) => [
          ...messages,
          { role: 'assistant', content },
        ]);
      }

      return <div>{content}</div>;
    },
    tools: {
      deploy: {
        description: 'Deploy repository to vercel',
        inputSchema: z.object({
          repositoryName: z
            .string()
            .describe('The name of the repository, example: vercel/ai-chatbot'),
        }),
        generate: async function* ({ repositoryName }) {
          yield <div>Cloning repository {repositoryName}...</div>; // [!code highlight:5]
          await new Promise(resolve => setTimeout(resolve, 3000));
          yield <div>Building repository {repositoryName}...</div>;
          await new Promise(resolve => setTimeout(resolve, 2000));
          return <div>{repositoryName} deployed!</div>;
        },
      },
    },
    onFinish: ({ usage }) => {
      const { promptTokens, completionTokens, totalTokens } = usage;
      // your own logic, e.g. for saving the chat history or recording usage
      console.log('Prompt tokens:', promptTokens);
      console.log('Completion tokens:', completionTokens);
      console.log('Total tokens:', totalTokens);
    },
  });

  return {
    id: generateId(),
    role: 'assistant',
    display: result.value,
  };
}
```

```typescript filename='app/ai.ts'
import { createAI } from '@ai-sdk/rsc';
import { ServerMessage, ClientMessage, continueConversation } from './actions';

export const AI = createAI<ServerMessage[], ClientMessage[]>({
  actions: {
    continueConversation,
  },
  initialAIState: [],
  initialUIState: [],
});
```
